defmodule Mix.Tasks.AshPostgres.Install do
  @moduledoc "Installs AshPostgres. Should be run with `mix igniter.install ash_postgres`"
  @shortdoc @moduledoc
  require Igniter.Code.Common
  use Igniter.Mix.Task

  def igniter(igniter, _argv) do
    repo = Igniter.Code.Module.module_name("Repo")
    otp_app = Igniter.Project.Application.app_name()

    igniter
    |> Igniter.Project.Formatter.import_dep(:ash_postgres)
    |> setup_repo_module(otp_app, repo)
    |> configure_config(otp_app, repo)
    |> configure_dev(otp_app, repo)
    |> configure_test(otp_app, repo)
    |> configure_runtime(otp_app, repo)
    |> Igniter.Project.Application.add_new_child(repo)
    |> Ash.Igniter.codegen("install_ash_postgres")
  end

  defp configure_config(igniter, otp_app, repo) do
    Igniter.Project.Config.configure(
      igniter,
      "config.exs",
      otp_app,
      [:ecto_repos],
      [repo],
      updater: fn zipper ->
        Igniter.Code.List.prepend_new_to_list(
          zipper,
          repo
        )
      end
    )
  end

  defp configure_runtime(igniter, otp_app, repo) do
    default_runtime = """
    import Config

    if config_env() == :prod do
      database_url =
        System.get_env("DATABASE_URL") ||
          raise \"\"\"
          environment variable DATABASE_URL is missing.
          For example: ecto://USER:PASS@HOST/DATABASE
          \"\"\"

      config #{inspect(otp_app)}, #{inspect(repo)},
        url: database_url,
        pool_size: String.to_integer(System.get_env("POOL_SIZE") || "10")
    end
    """

    igniter
    |> Igniter.create_or_update_elixir_file("config/runtime.exs", default_runtime, fn zipper ->
      if Igniter.Project.Config.configures?(zipper, [repo, :url], otp_app) do
        zipper
      else
        patterns = [
          """
          if config_env() == :prod do
            __cursor__()
          end
          """,
          """
          if :prod == config_env() do
            __cursor__()
          end
          """
        ]

        zipper
        |> Igniter.Code.Common.move_to_cursor_match_in_scope(patterns)
        |> case do
          {:ok, zipper} ->
            case Igniter.Code.Function.move_to_function_call_in_current_scope(
                   zipper,
                   :=,
                   2,
                   fn call ->
                     Igniter.Code.Function.argument_matches_predicate?(
                       call,
                       0,
                       &match?({:database_url, _, Elixir}, &1)
                     )
                   end
                 ) do
              {:ok, zipper} ->
                zipper
                |> Igniter.Project.Config.modify_configuration_code(
                  [repo, :url],
                  otp_app,
                  {:database_url, [], Elixir}
                )
                |> Igniter.Project.Config.modify_configuration_code(
                  [repo, :pool_size],
                  otp_app,
                  quote do
                    String.to_integer(System.get_env("POOL_SIZE") || "10")
                  end
                )
                |> then(&{:ok, &1})

              :error ->
                Igniter.Code.Common.add_code(zipper, """
                  database_url =
                    System.get_env("DATABASE_URL") ||
                      raise \"\"\"
                      environment variable DATABASE_URL is missing.
                      For example: ecto://USER:PASS@HOST/DATABASE
                      \"\"\"

                  config #{inspect(otp_app)}, Helpdesk.Repo,
                    url: database_url,
                    pool_size: String.to_integer(System.get_env("POOL_SIZE") || "10")
                """)
            end

          :error ->
            Igniter.Code.Common.add_code(zipper, """
            if config_env() == :prod do
              database_url =
                System.get_env("DATABASE_URL") ||
                  raise \"\"\"
                  environment variable DATABASE_URL is missing.
                  For example: ecto://USER:PASS@HOST/DATABASE
                  \"\"\"

              config #{inspect(otp_app)}, Helpdesk.Repo,
                url: database_url,
                pool_size: String.to_integer(System.get_env("POOL_SIZE") || "10")
            end
            """)
        end
      end
    end)
  end

  defp configure_dev(igniter, otp_app, repo) do
    igniter
    |> Igniter.Project.Config.configure_new("dev.exs", otp_app, [repo, :username], "postgres")
    |> Igniter.Project.Config.configure_new("dev.exs", otp_app, [repo, :password], "postgres")
    |> Igniter.Project.Config.configure_new("dev.exs", otp_app, [repo, :hostname], "localhost")
    |> Igniter.Project.Config.configure_new(
      "dev.exs",
      otp_app,
      [repo, :database],
      "#{otp_app}_dev"
    )
    |> Igniter.Project.Config.configure_new(
      "dev.exs",
      otp_app,
      [repo, :show_sensitive_data_on_connection_error],
      true
    )
    |> Igniter.Project.Config.configure_new("dev.exs", otp_app, [repo, :pool_size], 10)
  end

  defp configure_test(igniter, otp_app, repo) do
    database =
      {:<<>>, [],
       [
         "#{otp_app}_test",
         {:"::", [],
          [
            {{:., [], [Kernel, :to_string]}, [from_interpolation: true],
             [
               {{:., [], [{:__aliases__, [alias: false], [:System]}, :get_env]}, [],
                ["MIX_TEST_PARTITION"]}
             ]},
            {:binary, [], Elixir}
          ]}
       ]}
      |> Sourceror.to_string()
      |> Sourceror.parse_string!()

    igniter
    |> Igniter.Project.Config.configure_new("test.exs", otp_app, [repo, :username], "postgres")
    |> Igniter.Project.Config.configure_new("test.exs", otp_app, [repo, :password], "postgres")
    |> Igniter.Project.Config.configure_new("test.exs", otp_app, [repo, :hostname], "localhost")
    |> Igniter.Project.Config.configure_new(
      "test.exs",
      otp_app,
      [repo, :database],
      {:code, database}
    )
    |> Igniter.Project.Config.configure_new(
      "test.exs",
      otp_app,
      [repo, :pool],
      Ecto.Adapters.SQL.Sandbox
    )
    |> Igniter.Project.Config.configure_new("test.exs", otp_app, [repo, :pool_size], 10)
  end

  defp setup_repo_module(igniter, otp_app, repo) do
    default_repo_contents =
      """
      use AshPostgres.Repo, otp_app: #{inspect(otp_app)}

      def installed_extensions do
        # Add extensions here, and the migration generator will install them.
        ["ash-functions"]
      end
      """

    Igniter.Code.Module.find_and_update_or_create_module(
      igniter,
      repo,
      default_repo_contents,
      fn zipper ->
        zipper
        |> set_otp_app(otp_app)
        |> Sourceror.Zipper.top()
        |> use_ash_postgres_instead_of_ecto()
        |> Sourceror.Zipper.top()
        |> remove_adapter_option()
        |> Sourceror.Zipper.top()
        |> configure_installed_extensions_function()
        |> then(&{:ok, &1})
      end
    )
  end

  defp use_ash_postgres_instead_of_ecto(zipper) do
    with {:ok, zipper} <- Igniter.Code.Module.move_to_module_using(zipper, Ecto.Repo),
         {:ok, zipper} <- Igniter.Code.Module.move_to_use(zipper, Ecto.Repo),
         {:ok, zipper} <-
           Igniter.Code.Function.update_nth_argument(zipper, 0, fn zipper ->
             {:ok, Igniter.Code.Common.replace_code(zipper, AshPostgres.Repo)}
           end) do
      zipper
    else
      _ ->
        zipper
    end
  end

  defp remove_adapter_option(zipper) do
    with {:ok, zipper} <- Igniter.Code.Module.move_to_module_using(zipper, AshPostgres.Repo),
         {:ok, zipper} <- Igniter.Code.Module.move_to_use(zipper, AshPostgres.Repo),
         {:ok, zipper} <-
           Igniter.Code.Function.update_nth_argument(zipper, 1, fn values_zipper ->
             Igniter.Code.Keyword.remove_keyword_key(values_zipper, :adapter)
           end) do
      zipper
    else
      _ ->
        zipper
    end
  end

  defp set_otp_app(zipper, otp_app) do
    with {:ok, zipper} <- Igniter.Code.Module.move_to_module_using(zipper, AshPostgres.Repo),
         {:ok, zipper} <- Igniter.Code.Module.move_to_use(zipper, AshPostgres.Repo),
         {:ok, zipper} <-
           Igniter.Code.Function.update_nth_argument(zipper, 0, fn zipper ->
             {:ok, Igniter.Code.Common.replace_code(zipper, AshPostgres.Repo)}
           end),
         {:ok, zipper} <-
           Igniter.Code.Function.update_nth_argument(zipper, 1, fn values_zipper ->
             values_zipper
             |> Igniter.Code.Keyword.set_keyword_key(:otp_app, otp_app, fn x -> {:ok, x} end)
           end) do
      zipper
    else
      _ ->
        zipper
    end
  end

  defp configure_installed_extensions_function(zipper) do
    case Igniter.Code.Module.move_to_module_using(zipper, AshPostgres.Repo) do
      {:ok, zipper} ->
        case Igniter.Code.Module.move_to_def(zipper, :installed_extensions, 0) do
          {:ok, zipper} ->
            case Igniter.Code.Common.move_right(zipper, &Igniter.Code.List.list?/1) do
              {:ok, zipper} ->
                Igniter.Code.List.append_new_to_list(zipper, "ash-functions")

              :error ->
                {:error, "installed_extensions/0 doesn't return a list"}
            end

          _ ->
            Igniter.Code.Common.add_code(zipper, """
            def installed_extensions do
              # Add extensions here, and the migration generator will install them.
              ["ash-functions"]
            end
            """)
        end

      _ ->
        zipper
    end
  end
end